This exploratory application proposes to develop a quantitative real-time assay to detect residual disease in children with B-cell non-Hodgkin lymphoma (NHL) with the long term goal to be used clinically to assess treatment response or determine if intervention is needed. Although the majority of children diagnosed with B-cell NHL respond well to treatment, up to 30-40% still relapse or do not respond to therapy. One potential mechanism to identify these high-risk cases is to determine if minimal residual disease (MRD) is still present during primary therapy. While it remains to be shown if early intervention in pediatric B-cell NHL cases with residual disease is effective, if we translate the experience from other pediatric malignancies, it is likely that improvements in real-time assessment of residual disease in pediatric B-cell NHL are warranted. Capitalizing on the current experience in the lab with quantitative real-time PCR, (QRT-PCR), the objective of this exploratory application is to design and test the feasibility of a QRT-PCR assay to assess MRD in specimens from children diagnosed with B-cell NHL. The focus of this project will be to design markers from immunoglobulin heavy chain and/or T-cell receptor genes that are aberrant in childhood NHL using QRT-PCR without the need of diagnostic tissue from the original tumor. Our hypothesis is that a QRT-PCR assay is efficient in measuring MRD in clinical specimens from children with B-cell NHL; without diagnostic tissue available. To further expand upon the assay that will be developed, MRD specimens that are identified will be tested for mitochondrial DNA to study a potential mechanism for residual disease from persistent or compensatory increase in mitochondria, a source of energy for the cells. This will incorporate mtDNA assays currently established in the lab. This proposal is innovative by proposing to identify MRD in pediatric B-cell NHL without the need of initial or diagnostic tissue, and at the same time being able to take advantage of ongoing retrospective studies with pediatric B-cell NHL clinical specimens. The significance of the study lies in developing an assay which could potentially impact and improve the prognosis of children diagnosed with B-cell NHL. The assay developed by this exploratory proposal could be incorporated into pediatric B-cell NHL studies to assess MRD on therapy or to assess the efficacy of innovative therapies. [unreadable] [unreadable] [unreadable]